“I’m just the gay uncle,” Jack keeps saying in Glenn Gaylord’s plodding drama “I Do.” But is he? The movie shows one thing but insists on another.

After a long windup involving lots of exposition and a little tragedy, Jack (David W. Ross, who also wrote the screenplay), a British man living in New York, functionally becomes a surrogate father to his young niece, Tara (Jessica Tyler Brown). The filmmakers take pains to show how important the relationship is to Jack and the child (a movie kid, armed with from-the-mouths-of-babes aperçus). And then they make Tara a problem holding Jack back from dating, from living his “own” life — as if these were somehow incompatible.

The primary story involves Jack’s need for a green card. Although he has been in the United States since he was 17, he now has visa problems. The explanation? Everything’s harder since Sept. 11. In a better movie you might play along with contrived plot twists and fake obstacles, but watching “I Do,” a movie with thin characters and a languorous pace, you find yourself talking back to the screen.

When Jack meets a fella, Mano (Maurice Compte), a sweet architect from Spain, politically pointed complications ensue. Mano, it turns out, was born in America, but even if he were to marry Jack, the federal government wouldn’t honor the marriage, hence no green card. And then Mano is called back to Spain. Should Jack go or stay? Lead his “own” life or not? And who’s at fault — unenlightened government or overreaching screenwriter?